EP0999476A1 - Procédé de production de toner - Google Patents

Procédé de production de toner Download PDF

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Publication number
EP0999476A1
EP0999476A1 EP99122150A EP99122150A EP0999476A1 EP 0999476 A1 EP0999476 A1 EP 0999476A1 EP 99122150 A EP99122150 A EP 99122150A EP 99122150 A EP99122150 A EP 99122150A EP 0999476 A1 EP0999476 A1 EP 0999476A1
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Prior art keywords
particle
liquid
dispersion
monomer mixture
fine
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EP99122150A
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German (de)
English (en)
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EP0999476B1 (fr
Inventor
Yoshinori c/o Canon K. K. Tsuji
Atsushi c/o Canon K. K. Kubo
Minoru c/o Canon K. K. Ohmura
Hitoshi c/o Canon K. K. Kanda
Takeshi c/o Canon K. K. Tsujino
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Canon Inc
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Canon Inc
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0802—Preparation methods
    • G03G9/0804—Preparation methods whereby the components are brought together in a liquid dispersing medium
    • G03G9/0806—Preparation methods whereby the components are brought together in a liquid dispersing medium whereby chemical synthesis of at least one of the toner components takes place
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
    • B01F27/27—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices
    • B01F27/272—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed axially between the surfaces of the rotor and the stator, e.g. the stator rotor system formed by conical or cylindrical surfaces
    • B01F27/2722—Mixers with stator-rotor systems, e.g. with intermeshing teeth or cylinders or having orifices with means for moving the materials to be mixed axially between the surfaces of the rotor and the stator, e.g. the stator rotor system formed by conical or cylindrical surfaces provided with ribs, ridges or grooves on one surface

Definitions

  • This invention relates to a process for producing a toner having a good electrophotographic performance, having toner particles in which a fine-particle colorant stands finely and uniformly dispersed. More particularly, this invention relates to a process for producing a toner by polymerizing polymerizable monomers in an aqueous medium to form toner particles; the monomers being present in particles of a polymerizable monomer composition in which a fine-particle colorant stands finely and uniformly dispersed.
  • a number of methods as disclosed in U.S. Patent No. 2,297,691, etc. are known as electrophotography.
  • copies or prints are obtained by forming an electrostatic latent image on a photosensitive member, subsequently developing the electrostatic latent image by the use of a toner to form a toner image, transferring the toner image to a transfer medium such as paper as occasion calls, and thereafter fixing the toner image onto the transfer medium by the action of heat, pressure, heat-and-pressure or solvent vapor.
  • a variety of methods have been proposed, and methods suited for individual image-forming processes are employed.
  • Toners used for such purpose have been commonly produced by melt-kneading colorants comprising dyes or pigments, into thermoplastic resins to effect uniform dispersion, followed by pulverization using a fine grinding mill and classification using a classifier to produce toners having the desired particle diameters.
  • toners can be produced by such a production method, but there is a limit to the range in which toner materials are selected.
  • colorant-dispersed resins must be brittle enough to be pulverizable with ease by means of a fine grinding mill economically available.
  • Such colorant-dispersed resin having been made brittle tend to result in a broad particle size distribution of the particles formed when actually pulverized at a high speed, especially causing a problem that relatively large particles tend to be produced.
  • highly brittle materials tend to be further pulverized in developing assemblies of copying machines or the like.
  • toners produced by suspension polymerization toners produced by various polymerization and their production processes are disclosed in Japanese Patent Publications No. 36-10231, No. 43-10799, No. 51-14895 and so forth.
  • a polymerizable monomer, a colorant and a polymerization initiator, and also optionally a cross-linking agent, a charge control agent and other additives are uniformly dissolved or dispersed to form a polymerizable monomer composition.
  • this polymerizable monomer composition is dispersed in a continuous phase (e.g., an aqueous medium) containing a dispersion stabilizer, by means of a suitable agitator, and is simultaneously subjected to polymerization reaction to obtain toner particles having the desired particle diameters.
  • a continuous phase e.g., an aqueous medium
  • a dispersion stabilizer e.g., a dispersion stabilizer
  • the toner particles are not required to be brittle, and hence soft materials can be used as the resin. Also, colorants do not come bare to the surfaces of toner particles, and hence the toner particles having a uniform triboelectric charging performance can be obtained.
  • This method has such advantages. Also, since the toner particles obtained have a relatively sharp particle size distribution, the step of classification can be omitted, or, even when classified, toner particles can be obtained in a high yield.
  • the method also has the advantage that, since a low-softening substance can be encapsulated in toner particles in a large quantity, the toner particles obtained have a superior anti-offset properties.
  • Dyno-Mill having been made commercially available from Shinmaru Enterprises Corporation as disclosed in Japanese Patent Application Laid-open No. 6-11900; or a Coball-Mill, manufactured by Shinko Pantec Co., Ltd. as disclosed in Japanese Patent Application Laid-open No. 6-75429.
  • Reference numeral 121 denotes a main-body casing; 122, a material feed opening; 123, a discharge opening; 124, an agitator shaft; 125, media; 126, a circulating pump; 127, a holding tank; 128, agitator disks; and 129, a motor.
  • a dispersion target liquid material put into the holding tank 127 is fed through the material feed opening 122 by means of the circulating pump 126, passed through the layers of media 125 repeating their motion by a rotational force of the agitator disks 128 to effect dispersion, then separated from the media, thereafter discharged through the discharge opening 123, and returned to the holding tank 237. This cycle is repeated to carry out dispersion.
  • Reference numeral 231 denotes a main-body casing; 232, a material feed opening; 233, a discharge opening; 234, a media separator; 235, media layers; 236, a circulating pump; 237, a holding tank; and 238, a rotor.
  • a dispersion target liquid material put into the holding tank 237 is fed through the material feed opening 232 by means of the circulating pump 236, passed through the media layers 235 repeating their motion by a rotational force of the rotor 238 to effect dispersion, then separated from the media by the media separator 234, thereafter discharged through the discharge opening 233, and returned to the holding tank 237. This cycle is repeated to carry out dispersion.
  • a decrease of image density may occur when images are formed using a toner having toner particles obtained using a
  • An object of the present invention is to provide a toner production process having solved the problems discussed above.
  • Another object of the present invention is to provide, in a process for producing toner by polymerization, a production process by which a toner having a colorant dispersed more uniformly and promising a good image density can be produced in a good efficiency and stably.
  • Still another object of the present invention is to provide, in a process for producing toner by polymerization, a production process by which a toner being uniform in quality and having a sharp particle size distribution can be produced in a good efficiency and stably.
  • the present invention provides a process for producing a toner having toner particles, comprising;
  • the present invention also provides a process for producing a toner having toner particles, comprising;
  • the present invention still also provides a process for producing a toner having toner particles, comprising;
  • colorants can be dispersed in polymerizable monomers in a short time and stably when dispersed by means of a media type dispersion machine in which the direction of the flow of a monomer mixture is in agreement with the direction of the centrifugal force produced by the rotation of a rotor, thus they have accomplished the present invention.
  • Figs. 1 to 5 are preferably used.
  • Fig. 1 shows an example of a dispersion system incorporated with a media particle agitation type wet-dispersion machine, used in the present invention.
  • Fig. 2 shows an example of a dispersion system incorporated with a media particle agitation type wet-dispersion machine and a viscosity measuring system, used in the present invention.
  • Fig. 3 is a side view of the dispersion machine main body used in the present invention.
  • Fig. 4 is a cross-sectional view along the line 4-4 in Figs. 1 and 2
  • Fig. 5 a cross-sectional view along the line 5-5 in Fig. 3.
  • a dispersion machine 1 shown in Figs. 1 to 5 comprises a casing 2 and provided on its inside with a rotor 3 for agitating media particles 5 and, along the periphery of the rotor, a separator 4 having slits 4a for separating the media particles 5 from a liquid monomer mixture. Centrifugal force is produced by rotating the rotor 3, and this centrifugal force causes the media particles 5 to form a layer on the separator 4 provided along the rotor's periphery. At the same time, the rotational force of the rotor 3 causes a rotary motion. Hence, a strong shear force is produced to disperse the fine-particle colorant in polymerizable monomers.
  • the liquid monomer mixture put into a holding tank 8 is fed into the dispersion machine 1 through a material feed opening 6 by means of a circulating pump 10, and, by the aid of the centrifugal force produced by the rotation of the rotor 3, it is passed through the media layer formed along the periphery of the rotor to become surely finely dispersed. Thereafter, the liquid monomer mixture is separated from the media particles 5 by the separator 4, then discharged out of the dispersion machine through a discharge opening 7, and returned to the holding tank 8 through a pipe provided with a viscometer 25 and/or a thermometer 12 and through a cooling means 11.
  • the monomer mixture held in the holding tank 8 is repeatedly circulated between the dispersion machine 1 and the holding tank 8, during which the fine-particle colorant is dispersed in the polymerizable monomer uniformly and in a good efficiency.
  • the rotor 3 is perspectively illustrated in Fig. 6.
  • the separator 4 is perspectively illustrated in Fig. 7.
  • the polymerizable monomer, colorant, charge control agent and so forth may be put into the holding tank 8 directly, or may provisionally be mixed and thereafter put into the holding tank 8.
  • a heat exchanger may be provided as a cooling means in the line of the circulation system so that the dispersion system can be operated while making heat exchange.
  • the monomer mixture may preferably be controlled to have a liquid temperature of from 10 to 40°C, and more preferably from 15 to 35°C.
  • the fine-particle-colorant-containing monomer mixture discharged through the liquid-discharge opening may preferably have a viscosity of from 5 to 2,500 mPa ⁇ s, more preferably from 20 to 2,000 mPa ⁇ s, and still more preferably from 50 to 2,000 mPa ⁇ s.
  • the media particles used may preferably have a diameter within the range of from 0.1 mm to 2 mm in view of the dispersibility of colorants in polymerizable monomers.
  • the relationship between a total volume A of media particles present in the dispersion machine and a space volume B between the rotor 3 and the separator 4 may preferably be in the range of: 0.7 ⁇ A/B ⁇ 1.3.
  • the space volume B between the rotor 3 and the separator 4 corresponds to the total volume of the part shown in Fig. 4.
  • the rotor may preferably be rotated at a peripheral speed at the tip portion ranging from 5 to 20 m/s, and more preferably from 7 to 17 m/s.
  • the viscometer 25 may be provided between the liquid-discharge opening 7 and the liquid-feed opening 6 to measure the viscosity of the
  • Such a viscometer may specifically include a vibration viscometer FUM-80A Shield Type (manufactured by Yamaichi Denki K.K.) and MIV16001 ADF Type (manufactured by Sofraser Co., Ltd.).
  • a predetermined viscosity is previously set, and also two points are set for low-speed rotation and high-speed rotation as the number of revolutions of the rotor.
  • the rotor With the starting of operation, the rotor begins to be driven at a low-speed rotation and the viscometer set in the system begins to measure the viscosity of the monomer mixture.
  • the values of the viscosity of the fine-particle-colorant-containing monomer mixture, measured with the viscometer 25, are inputted to the personal computer 26.
  • signals for changing the rotor to the mode of high-speed rotation are outputted to make the rotor rotate at a high speed.
  • the dispersion is carried out while applying a pressure to the inside of the dispersion machine, and hence a valve 19 is provided on the downstream side of the discharge opening 7. This is preferable because the dispersion efficiency of colorants can be improved and also short pass can be prevented.
  • the dispersion may preferably be carried out for 10 to 300 minutes, and more preferably 20 to 180 minutes, as treating time.
  • Materials for the media particles used in the dispersion machine may include glass, steel, chromium alloys, alumina, zirconia, zircon and titania. Of these media materials, zirconia and titania are preferred in view of wear resistance.
  • Such a media type dispersion machine may specifically include SC mill (manufactured by Mitsui Mining & Smelting Co., Ltd.).
  • the process for producing toner particles by polymerization may include processes for producing toner particles directly by suspension polymerization as disclosed in Japanese Patent Publication No. 36-10231 and Japanese Patent Applications Laid-open No. 59-53856 and No. 59-61842.
  • seed polymerization may also preferably be used in which polymerizable monomers are additionally adsorbed on colorant-containing polymer particles once obtained, and thereafter polymerized using a polymerization initiator.
  • An example of a flow chart of the production of toner particles by polymerization is shown in Fig. 8.
  • the toner particles are incorporated with a low-softening substance in a large quantity from the viewpoint of fixing performance, it is important to encapsulate the low-softening substance in shell resin.
  • a low-softening substance whose material polarity in an aqueous medium is smaller than the main polymerizable monomer may be selected and also a small amount of resin or polymerizable monomer with a greater polarity than the main monomer may be added.
  • toner particles having a core/shell structure wherein the low-softening substance is covered with the shell resin can be obtained.
  • the particle size distribution and particle diameter of the toner particles may be controlled by a method in which the types and amounts of a slightly water-soluble inorganic salt and a dispersant having the action of protective colloids are changed, or by changing mechanical apparatus conditions (e.g., the conditions for agitation, such as the peripheral speed of the rotor, pass times and the shape of agitating blades, the shape of the vessel), or by controlling the concentration of solid matter in an aqueous solution, whereby the intended toner particles can be obtained.
  • mechanical apparatus conditions e.g., the conditions for agitation, such as the peripheral speed of the rotor, pass times and the shape of agitating blades, the shape of the vessel
  • the core/shell structure can be ascertained by observing cross sections of toner particles.
  • the cross sections of toner particles can be observed in the following way. Toner particles are well dispersed in a room temperature curing epoxy resin, followed by curing in an atmosphere of temperature 40°C for 2 days. The cured product obtained is dyed with triruthenium tetraoxide optionally in combination with triosmium tetraoxide. Thereafter, samples are cut out in slices by means of a microtome having a diamond cutter, to observe the form of cross sections of toner particles using a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the triruthenium tetraoxide dyeing method in order to form a contrast between the materials by utilizing some difference in crystallinity between the low-softening substance and the resin constituting the shell.
  • a typical example is shown in Fig. 9. It has been observed that toner particles produced in Examples given later have the structure wherein the low-softening substance is encapsulated with the shell resin.
  • the polymerizable monomer used to form the toner particles may include vinyl monomers.
  • vinyl monomers preferred are styrene monomers such as styrene, o-, m- or p-methylstyrene, and m- or p-ethylstyrene; acrylic or methacrylic acid ester monomers such as methyl acrylate or methacrylate, ethyl acrylate or methacrylate, propyl acrylate or methacrylate, butyl acrylate or methacrylate, octyl acrylate or methacrylate, dodecyl acrylate or methacrylate, stearyl acrylate or methacrylate, behenyl acrylate or methacrylate, 2-ethylhexyl acrylate or methacrylate, dimethylaminoethyl acrylate or methacrylate, and diethylaminoethyl acrylate or methacrylate; and
  • any of these may be used alone or in the form of an appropriate mixture of vinyl monomers so mixed that the theoretical glass transition temperature (Tg) as described in POLYMER HANDBOOK, 2nd Edition III, pp.139-192 (John Wiley & Sons, Inc.) ranges from 40 to 75°C. If the theoretical glass transition temperature is lower than 40°C, problems may arise in respect of storage stability of toners or running stability of developers. If on the other hand it is higher than 75°C, the fixing temperature of toner images may become higher. Especially in the case of color toners used to form full-color images, the color mixing performance of the respective color toners may lower, resulting in a poor color reproducibility, and also OHP images may have a low transparency.
  • Tg theoretical glass transition temperature
  • the low-softening substance used in the toner particles according to the present invention it is preferable to use a material showing a maximum endothermic peak temperature of from 40 to 90°C as measured according to ASTM D3418-8. If the maximum endothermic peak temperature is lower than 40°C, the low-softening substance may have a weak self-cohesive force, resulting in weak high-temperature anti-offset properties. This is not desirable for color toners used to form full-color images. If on the other hand the maximum endothermic peak temperature is higher than 90°C, fixing temperature may become higher to make it difficult to smoothen the fixed-image surface appropriately. This is undesirable in view of color mixing performance.
  • the low-softening substance may precipitate from polymerizable monomers to hinder the granulation undesirably, because the granulation and polymerization are carried out in an aqueous medium.
  • the peak top temperature of the maximum endothermic peak is measured using, e.g., DSC-7, manufactured by Perkin Elmer Co.
  • the temperature at the detecting portion of the device is corrected on the basis of melting points of indium and zinc, and the calorie is corrected on the basis of heat of fusion of indium.
  • the sample is put in a pan made of aluminum and an empty pan is set as a control, to make measurement at a rate of temperature rise of 10°C/min.
  • the low-softening substance may specifically include paraffin waxes, polyolefin waxes, Fischer-Tropsch waxes, amide waxes, higher fatty acids, ester waxes, and derivatives of these or grafted or blocked compounds of these.
  • Ester waxes having at least one long-chain ester moiety having at least 10 carbon atoms as shown by the following structural formulas are particularly preferred in the present invention as being effective for the high temperature anti-offset properties without impairment of the transparency required for OHP.
  • Structural formulas of the ester waxes preferred in the present invention are shown below as Formulas (I) to (VI).
  • R 1 -COO-(CH 2 ) n a C[(CH 2 ) m -OCO-R 2 ] b
  • a and b each represent an integer of 0 to 4, provided that a + b is 4
  • R 1 and R 2 each represent an organic group having 1 to 40 carbon atoms, provided that a difference in the number of carbon atoms between R 1 and R 2 is 10 or more
  • n and m each represent an integer of 0 to 15, provided that n and m are not 0 at the same time.
  • a and b each represent an integer of 0 to 3, provided that a + b is 3;
  • R 1 and R 2 each represent an organic group having 1 to 40 carbon atoms, provided that a difference in the number of carbon atoms between R 1 and R 2 is 10 or more;
  • R 3 represents an organic group having 1 or more carbon atoms;
  • n and m each represent an integer of 0 to 15, provided that n and m are not 0 at the same time.
  • R 1 -COO-R 2 wherein R 1 and R 2 may be the same or different and each represent a hydrocarbon group having 15 to 45 carbon atoms.
  • R 1 and R 3 each represent an organic group having 6 to 32 carbon atoms; R 1 and R 3 may be the same or different; and R 2 represents an organic group having 1 to 20 carbon atoms.
  • R 1 and R 3 each represent an organic group having 6 to 32 carbon atoms; R 1 and R 3 may be the same or different; and R 2 represents -CH 2 CH 2 OC 6 H 4 OCH 2 CH 2 -, or -(CH 2 ) n -; and m represents an integer of 1 to 10, and n an integer of 1 to 20.
  • the ester wax preferably used in the present invention may preferably be those having a hardness of from 0.5 to 5.0.
  • the hardness of the ester wax is a value obtained by preparing a sample having a cylindrical shape of 20 mm diameter and 5 mm thick and thereafter measuring Vickers hardness by the use of, e.g., a dynamic ultrafine hardness meter (DUH-200) manufactured by Shimadzu Corporation. As measurement conditions, a penetrator's position is moved by 10 ⁇ m under conditions of a load of 0.5 g and a loading rate of 9.67 mm/sec. Thereafter, it is kept as it is for 15 seconds, and a depression made on the sample is measured to determine Vickers hardness.
  • ester wax has a hardness lower than 0.5, fixing assemblies may have a great dependence on pressure and on process speed, tending to lower the high-temperature anti-offset effect. If on the other hand it has a hardness higher than 5.0, the toner may have a low storage stability, and the wax itself may also have a weak self-cohesive force to likewise lower the high-temperature anti-offset properties.
  • the ester wax may include the following compounds. CH 3 -(CH 2 ) 20 COO(CH 2 ) 21 CH 3 CH 3 -(CH 2 ) 16 COO(CH 2 ) 21 CH 3 CH 3 -(CH 2 ) 39 COO(CH 2 ) 17 CH 3 CH 3 -(CH 2 ) 20 COO(CH 2 ) 17 CH 3
  • the low-softening substance may preferably be added in the toner particles in an amount of from 5 to 30% by weight. Its addition in an amount less than 5% by weight may lower the high-temperature anti-offset properties.
  • the back-side images tend to show the phenomenon of offset when double-sided images are fixed.
  • the toner particles tend to coalesce one another during granulation, so that those having a broad particle size distribution tend to be produced.
  • a polar resin in addition to the shell resin.
  • copolymers of styrene with acrylic or methacrylic acid, maleic acid copolymers, saturated polyester resins, unsaturated polyester resins and epoxy resins are preferably used.
  • the polar resin may particularly preferably be those not containing in the molecule any unsaturated groups that may react with the shell resin and the polymerizable monomer.
  • a polar resin having such unsaturated groups is used, cross-linking reaction takes place between the polar resin and the polymerizable monomer that forms the shell resin layer, so that the shell resin comes to have a too high molecular weight for the toners for forming full-color images and is disadvantageous for color mixing performance of color toners.
  • a resin is not preferable.
  • the fine-particle colorant used in the present invention carbon black, magnetic materials, and colorants toned in black by the use of yellow, magenta and cyan colorants shown below may be used as black colorants.
  • the fine-particle colorant may preferably comprise primary particles having a number-average particle diameter of 0.5 ⁇ m or smaller, more preferably 0.3 ⁇ m or smaller.
  • condensation azo compounds As a yellow colorant, condensation azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds and allylamide compounds are used. Stated specifically, C.I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147 and 168 are preferably used.
  • condensation azo compounds As a magenta colorant, condensation azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds are used. Stated specifically, C.I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221 and 254 are particularly preferred.
  • cyan colorant copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds and basic dye lake compounds may be used. Stated specifically, C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62 and 66 may particularly preferably be used.
  • any of these colorants may be used alone, in the form of a mixture, or in the state of a solid solution.
  • the colorants are selected taking account of hue angle, chroma, brightness, weatherability, transparency on OHP films and dispersibility in toner particles.
  • the non-magnetic colorant may be added in an amount of from 1 to 20 parts by weight based on 100 parts by weight of the monomer mixture, finally.
  • the colorant may preferably be contained in an amount of from 1 to 20 parts by weight based on 100 parts by weight of the toner particles.
  • a magnetic material in the case when a magnetic material is used as the black colorant, it may be used in an amount of from 40 to 150 parts by weight based on 100 parts by weight of the monomer mixture.
  • charge control agent used in the present invention known agents may be used. It is preferable to use charge control agents that are colorless, make toner charging speed higher and are capable of stably maintaining a constant charge quantity. Also, charge control agents having no polymerization inhibitory action and being insoluble in aqueous mediums are particularly preferred. As specific compounds, they may include, as negative charge control agents, metal compounds of salicylic acid, naphthoic acid or dicarboxylic acids, polymer type compounds having sulfonic acid or carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds and carixarene.
  • positive charge control agents may include quaternary ammonium salts, polymer type compounds having such a quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds. Any of these charge control agents may preferably be used in a amount of from 0.5 to 10 parts by weight based on 100 parts by weight of the monomer mixture. In the present invention, however, the addition of the charge control agent is not essential. In the case when two-component development is employed, the triboelectric charging between a carrier and a toner may be utilized. In the case when non-magnetic one-component blade coating development is employed, the triboelectric charging between a blade member or sleeve member and a toner may be utilized. Hence, the charge control agent need not necessarily be contained in the toner particles.
  • a polymerization initiator used to form the toner particles according to the present invention may include azo or diazo type polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile), 1,1'-azobis-(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; and peroxide type polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide and t-butylperoxydiethyl hexanoate.
  • azo or diazo type polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2
  • the polymerization initiator may usually be used in an amount of from 0.5 to 20% by weight based on the weight of the polymerizable monomers, which varies depending on the intended degree of polymerization.
  • the polymerization initiator may a little vary in type depending on the methods for polymerization, and may be used alone or in the form of a mixture, making reference to its 10-hour half-life period temperature.
  • any known cross-linking agent, chain transfer agent and polymerization inhibitor may further be added.
  • the dispersion stabilizer used may include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica and alumina. Any of the stabilizers may preferably be used in an amount of from 0.2 to 20 parts by weight based on 100 parts by weight of the polymerizable monomer.
  • the inorganic compound may be formed in an aqueous medium.
  • an aqueous sodium phosphate solution and an aqueous calcium chloride solution may be mixed under high-speed agitation.
  • a surface-active agent may be used.
  • the surface-active agent it may include sodium dodecylbenzenesulfate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, sodium oleate, sodium laurate, potassium stearate and calcium oleate.
  • the colorant, the charge control agent, the low-softening substance (having the function as a release agent) and other additives are added to obtain a monomer mixture, which is then dispersed by means of the media type dispersion machine in which the direction of the flow of the monomer mixture is in agreement with the direction of the centrifugal force.
  • the polymerization initiator may be added to the monomer mixture to prepare a polymerizable monomer composition, which is then uniformly dispersed in the aqueous dispersion medium containing the dispersion stabilizer, by means of a conventional agitator, Clear Mix, homogenizer, homomixer or ultrasonic dispersion machine.
  • Granulation is carried out preferably while controlling the agitation speed and time so that droplets of the monomer mixture can have the desired toner particle size.
  • agitation may be carried out to such an extent that the state of particles is maintained and the particles can be prevented from settling, by the acton of the dispersion stabilizer.
  • polymerization may be carried out at a temperature set at 40°C or above, usually from 50 to 90°C.
  • the temperature may be raised, and also the aqueous dispersion medium may be removed in part from the reaction system at the latter half of the reaction or after the reaction has been completed, in order to remove unreacted polymerizable monomers, by-products and so forth which are causative of a smell at the time of toner fixing.
  • the toner particles formed are collected by washing and filtration, followed by drying to produce toner particles.
  • the polymerization initiator may be added to the aqueous dispersion medium after the granulation of the polymerizable monomer composition in the aqueous dispersion medium, to polymerize polymerizable monomers of the particles.
  • water may usually be used as an aqueous medium preferably in an amount of from 300 to 3,000 parts by weight based on 100 parts by weight of the monomer mixture.
  • Particle size distribution of the toner can be measured by various methods. Here, it is measured by the Coulter method, using a Coulter Multisizer.
  • Coulter Multisizer manufactured by Coulter Electronics, Inc.
  • An interface manufactured by Nikkaki K.K.
  • a personal computer PC9801 manufactured by NEC Corporation
  • an electrolytic solution an aqueous 1% NaCl solution is prepared using first-grade sodium chloride.
  • Measurement is made by adding as a dispersant 0.1 to 5 ml of a surface active agent, preferably alkylbenzene sulfonate, to 100 to 150 ml of the above aqueous electrolytic solution, and further adding 2 to 20 mg of a sample to be measured.
  • the electrolytic solution in which the sample has been suspended is subjected to dispersion for about 1 minute to about 3 minutes in an ultrasonic dispersion machine.
  • the values are determined by measuring the particle size distribution of particles of 2 to 40 ⁇ m on the basis of number, by means of the Coulter Multisizer, using an aperture of 100 ⁇ m as its aperture.
  • the fine-particle colorant stands dispersed in the monomer mixture finely and uniformly, and hence a toner with small particle diameters, having a weight-average particle diameter of from 4 to 10 ⁇ m (more preferably from 4 to 9 ⁇ m) and a sharp particle size distribution that the coefficient of variation in number distribution is 35% or less (more preferably 30% or less), can be formed in a good efficiency and in a good yield.
  • Coefficient of variation (%) [S/D1] x 100 where S represents a standard deviation in number distribution of toner particles, and D1 represents a number-average particle diameter ( ⁇ m) of the toner particles.
  • the step of dispersion was carried out using the dispersion system shown in Fig. 2.
  • 170 parts by weight of styrene monomer, 10 parts by weight of a fine-particle magenta colorant (C.I. Pigment Red 122; number average particle diameter: 0.05 ⁇ m or smaller) and 3 parts by weight of a negative charge control agent (a dialkylsalicylic acid metal compound) were introduced into a holding tank 8.
  • the agitating blades were rotated by means of an agitator motor 13 to prepare a styrene monomer mixture containing the fine-particle magenta colorant.
  • the styrene monomer mixture thus prepared was introduced into the media particle agitation type wet-dispersion machine 1 by means of a circulating pump 10; the dispersion machine being loaded with spherical media particles (spherical zirconia particles of 0.3 mm diameter) at a packing of 8 x 10 -4 m 3 (about 6.8 x 10 7 particles).
  • the media particle agitation type wet-dispersion machine 1 has a rotor 3 (diameter: 220 mm) in a casing 2.
  • the styrene monomer mixture was introduced into it from a first wall surface having a liquid-feed opening 6 at the middle area while rotating the rotor 3 at a number of revolutions of 8.7 r.p.s. (peripheral speed: 6 m/s) by means of a drive shaft 21 driven by a motor the dispersion machine has.
  • the quantity of styrene monomer mixture introduced into the casing 2 was adjusted by means of the circulating pump 10 to come be 0.9 m 3 /h.
  • the styrene monomer mixture introduced through the liquid-feed opening 6 was transported toward a separator 4 from the middle of an inner chamber 22 by the aid of a centrifugal force produced by the rotation of the rotor 3.
  • the styrene monomer mixture containing the fine-particle colorant was further passed between layers of media particles flowing on the separator 4, whereupon the fine-particle colorant was made finer and dispersed in the styrene monomer mixture by the aid of the rotation of the rotor 3 and a shear force of media particles 5.
  • the styrene monomer mixture having the fine-particle colorant thus dispersed was transported to an outer chamber 23 through slits 4a.
  • the styrene monomer mixture was discharged out of the casing through a discharge opening 7 provided in the side wall (a second wall surface), was passed through a valve 19, a thermometer 12 and a viscometer 25, and was introduced into the holding tank 8 through a cooling means 11.
  • the styrene monomer mixture discharged through the liquid-discharge opening 7 had a temperature of 25°C as measured with the thermometer 12.
  • the temperature of the styrene monomer mixture was adjusted to 20°C by means of the cooling means 11 through a feed opening 14 of which cooling water was kept introduced and through a discharge opening 15 of which the cooling water was kept discharged.
  • the styrene monomer mixture had a viscosity of 20 mPa ⁇ s. Power consumption was 7 kW.
  • the styrene monomer mixture showed a viscosity of 55 mPa ⁇ s. Accordingly, the number of revolutions of the rotor was changed to a high-speed rotation of 16.7 r.p.s. (peripheral speed: 11.5 m/s), where the fine-particle colorant was dispersed in the styrene monomer mixture over a period of 60 minutes. Power consumption shown after 10 minutes was at a constant value of 8.5 kW, and a fine-particle-colorant-containing monomer mixture finally obtained had a viscosity of 700 mPa ⁇ s. Thereafter, the styrene monomer mixture in which the fine-particle colorant had been dispersed finely and uniformly was transported to a preparation step by operating a three-way valve 20.
  • the dispersion formed was collected from the dispersion machine, where the dispersion was well collected. Also, after the dispersion step was completed, the media particles were visually examined, where the media particles were found not to have undergone any changes.
  • n-butyl acrylate monomer 20 parts by weight of a polar resin (saturated polyester resin: polyester resin produced by condensation polymerization of terephthalic acid with bisphenol A modified with propylene oxide; acid value: 13 mg KOH/g; main-peak molecular weight: 7,000) and 25 parts by weight of an ester wax [Ester Compound (1); DSC maximum endothermic peak temperature: about 60°C] were added to the styrene monomer mixture having 170 parts by weight of styrene monomer, 10 parts by weight of the fine-particle magenta colorant and 3 parts by weight of the negative charge control agent, and were mixed at 60°C, followed by further addition of 10 parts by weight of 2,2'-azobis-(2,4-dimethylvaleronitrile) as a polymerization initiator, thus a polymerizable monomer composition was prepared.
  • saturated polyester resin polyester resin produced by condensation polymerization of terephthalic acid with bisphenol A modified with propylene oxide; acid
  • the magenta toner particles thus obtained had a weight-average particle diameter of 6.5 ⁇ m.
  • the coefficient of variation in number distribution was 28%.
  • magenta toner particles obtained were found to have the structure as shown in Fig. 9 that the low-softening substance, ester wax was covered with the shell resin.
  • magenta toner particles thus obtained, 0.7 part by weight of hydrophobic fine silica powder having a specific surface area of 200 m 2 /g as measured by the BET method was externally added to prepare a magenta toner.
  • 93 parts by weight of an acryl-coated magnetic ferrite carrier was blended to produce a two-component developer.
  • This developer was put in a commercially available plain-paper color copying machine (Color Laser Copyer 500, manufactured by CANON INC.), and images were reproduced in an environment of 23°C/65%RH under a development contrast set at 300 V. On the images formed, their reflection density was measured with a densitometer Macbeth RD918 using an SPI filter (the same applies in the measurement of image density herein described later) to make evaluation.
  • Macbeth density As for evaluation criteria, an instance where the value of Macbeth density is 1.2 or more indicates a good image density; from 1.0 to less than 1.2, an image density slightly problematic on images but no problem in practical use; and less than 1.0, an image density considerably seriously affecting images and not desirable for products.
  • media particles material: zirconia
  • the styrene monomer mixture showed a viscosity of 53 mPa ⁇ s.
  • the number of revolutions of the rotor was changed to a high-speed rotation of 16.7 r.p.s. (peripheral speed: 11.5 m/s), where the fine-particle colorant was dispersed in the styrene monomer mixture over a period of 60 minutes.
  • Dispersion was carried out in the same manner as in Example 1 except that, after the styrene monomer mixture showed a viscosity of 55 mPa ⁇ s upon lapse of 10 minutes, the number of revolutions of the rotor was changed to a high-speed rotation of 20.8 r.p.s. (peripheral speed: 14.4 m/s). Power consumption shown after 10 minutes was at a constant value of 9.5 kW, and a fine-particle-colorant-containing monomer mixture finally obtained had a viscosity of 770 mPa ⁇ s. The subsequent procedure was repeated in the same manner as in Example 1 to obtain magenta toner particles. The magenta toner particles thus obtained had a weight-average particle diameter of 6.6 ⁇ m. The coefficient of variation in number distribution was 26%.
  • the dispersion machine was operated at a number of revolutions of 4.3 r.p.s. (peripheral speed: 6.2 m/s).
  • the circulating pump was so controlled that the flow rate of the mixture came to be 3.6 m 3 /h.
  • the viscosity of the styrene monomer mixture was 25 mPa ⁇ s and the power consumption was 28 kW. Thereafter, upon lapse of 15 minutes, the styrene monomer mixture showed a viscosity of 51 mPa ⁇ s. Accordingly, the number of revolutions of the rotor was changed to a high-speed rotation of 8.3 r.p.s. (peripheral speed: 11.8 m/s), where the fine-particle colorant was dispersed in the styrene monomer mixture over a period of 60 minutes. Power consumption shown after 15 minutes was at a constant value of 32 kW, and a fine-particle-colorant-containing monomer mixture finally obtained had a viscosity of 750 mPa ⁇ s.
  • the same n-butyl acrylate monomer, saturated polyester resin and ester wax [Ester Compound (1)] as those used in Example 1 were dissolved in the same way, followed by addition of 10 parts by weight of a polymerization initiator 2,2'-azobis-(2,4-dimethylvaleronitrile).
  • the mixture obtained was put into the aqueous dispersion medium to carry out granulation for 13 minutes.
  • the high-speed stirrer was changed to a stirrer having propeller stirring blades and reaction was carried out for at 60°C for 5 hours, and then the liquid temperature was raised to 80°C to carry out the reaction for 10 hours.
  • magenta toner particles After the polymerization was completed, a portion of the slurry formed was sampled, and further washed and dried to measure physical properties of the magenta toner particles obtained.
  • the magenta toner particles thus obtained had a weight-average particle diameter of 6.5 ⁇ m as measured with the Coulter counter. The coefficient of variation in number distribution was 28%.
  • the magenta particles were found to have the structure as shown in Fig. 9 that the low-softening substance Ester Compound (1) was covered with the shell resin.
  • magenta toner particles thus obtained, 0.7 part by weight of hydrophobic fine silica powder having a specific surface area of 200 m 2 /g as measured by the BET method was externally added to prepare a magenta toner.
  • 93 parts by weight of an acryl-coated magnetic ferrite carrier was blended to produce a two-component developer.
  • Example 1 The procedure of Example 1 was repeated except that, in the preparation step, 30 parts by weight of n-butyl acrylate monomer, 20 parts by weight of a polar resin (saturated polyester resin: polyester resin produced by condensation polymerization of terephthalic acid with bisphenol A modified with propylene oxide; acid value: 13 mg KOH/g; main-peak molecular weight: 7,000) and 25 parts by weight of an ester wax [Ester Compound (1); DSC maximum endothermic peak temperature: about 60°C] were added to a styrene monomer mixture having 170 parts by weight of the styrene monomer, 30 parts by weight of the fine-particle magenta colorant and 3 parts by weight of the negative charge control agent as obtained in a similar manner to that in the dispersion step of Example 1, followed by mixing at 60°C to obtain a polymerizable monomer composition, and this polymerizable monomer composition and 10 parts by weight of the polymerization initiator 2,2'-azobis-(2,4
  • Example 1 The procedure of Example 1 was repeated except that the polymerizable monomer composition obtained in Example 5 was put into an aqueous dispersion medium heated to a temperature of 60°C to carry out granulation for 13 minutes by means of the TK-homomixer and, after the high-speed stirrer was changed to a stirrer having propeller stirring blades, 10 parts by weight of the polymerization initiator 2,2'-azobis-(2,4-dimethylvaleronitrile) was added.
  • the magenta toner particles thus obtained had a weight-average particle diameter of 6.5 ⁇ m.
  • the coefficient of variation in number distribution was 28%.
  • the step of dispersion was carried out using the dispersion system shown in Fig. 1.
  • a fine-particle magenta colorant C.I. Pigment Red 122; number average particle diameter: 0.05 ⁇ m or smaller
  • a negative charge control agent a dialkylsalicylic acid metal compound
  • the styrene monomer mixture thus prepared was introduced into the media particle agitation type wet-dispersion machine 1 by means of a circulating pump 10; the dispersion machine being loaded with spherical media particles (spherical zirconia particles of 0.3 mm diameter) at a packing of 8 x 10 -4 m 3 (about 6.8 x 10 7 particles).
  • the media particle agitation type wet-dispersion machine 1 has a rotor 3 (diameter: 220 mm) in a casing 2.
  • the styrene monomer mixture was introduced into it from a first wall surface having a liquid-feed opening 6 at the middle area while rotating the rotor 3 at a number of revolutions of 16.7 r.p.s. (peripheral speed: 11.5 m/s) by means of a drive shaft 21 driven by a motor the dispersion machine has.
  • the quantity of styrene monomer mixture introduced into the casing 2 was adjusted by means of the circulating pump 10 to come be 0.9 m 3 /h.
  • the casing 2 was kept at an internal pressure of 196.1 kPa.
  • the styrene monomer mixture introduced through the liquid-feed opening 6 was transported toward a separator 4 from the middle of an inner chamber 22 by the aid of a centrifugal force produced by the rotation of the rotor 3.
  • the styrene monomer mixture containing the fine-particle colorant was further passed between layers of media particles fluidizing on the separator 4, whereupon the fine-particle colorant was made finer and dispersed in the styrene monomer mixture by the aid of the rotation of the rotor 3 and a shear force of media particles 5.
  • the styrene monomer mixture having the fine-particle colorant thus dispersed was transported to an outer chamber 23 through slits 4a.
  • the styrene monomer mixture was discharged out of the casing through a discharge opening 7 provided in the side wall (a second wall surface), was passed through a valve 19 and a thermometer 12, and was introduced into the holding tank 8 through a cooling means 11.
  • the styrene monomer mixture discharged through the liquid-feed opening 6 had a temperature of 29°C as measured with the thermometer 12.
  • the temperature of the styrene monomer mixture was adjusted to 20°C by means of the cooling means 11 through a feed opening 14 of which cooling water was kept introduced and through a discharge opening 15 of which the cooling water was kept discharged.
  • the motor for rotating the rotor at this stage showed a power consumption of 13 kW.
  • the power consumption decreased with time to come to be 8.5 kW after 10 minutes, and thereafter became constant at that value.
  • the dispersion step of dispersing the fine-particle colorant in the styrene monomer mixture was carried out for 60 minutes.
  • the styrene monomer mixture passed through the dispersion machine at about 36 times/hour. Thereafter, the styrene monomer mixture in which the fine-particle colorant had been dispersed finely and uniformly was transported to a preparation step by operating a three-way valve 20.
  • the dispersion was collected from the dispersion machine, where the dispersion was well collected. Also, after the dispersion step was completed, the media particles were visually examined, where the media particles were found not to have undergone any changes.
  • n-butyl acrylate monomer 20 parts by weight of a polar resin (saturated polyester resin: polyester resin produced by condensation polymerization of terephthalic acid with bisphenol A modified with propylene oxide; acid value: 13 mg KOH/g; main-peak molecular weight: 7,000) and 25 parts by weight of an ester wax [Ester Compound (1); DSC maximum endothermic peak temperature: about 60°C] were added to the styrene monomer mixture having 170 parts by weight of the styrene monomer, 10 parts by weight of the fine-particle magenta colorant and 3 parts by weight of the negative charge control agent, and were mixed at 60°C, followed by further addition of 10 parts by weight of 2,2'-azobis-(2,4-dimethylvaleronitrile) as a polymerization initiator, thus a polymerizable monomer composition was prepared.
  • saturated polyester resin polyester resin produced by condensation polymerization of terephthalic acid with bisphenol A modified with propylene oxide;
  • magenta toner particles obtained had a weight-average particle diameter of 6.5 ⁇ m as measured with the Coulter counter. The coefficient of variation in number distribution was 28%.
  • magenta toner particles obtained were found to have the structure as shown in Fig. 9 that the low-softening substance ester wax was covered with the shell resin.
  • magenta toner particles thus obtained, 0.7 part by weight of hydrophobic fine silica powder having a specific surface area of 200 m 2 /g as measured by the BET method was externally added to prepare a magenta toner.
  • 93 parts by weight of an acryl-coated magnetic ferrite carrier was blended to produce a two-component developer.
  • the motor for rotating the rotor at the drive initial stage showed a power consumption of 12.5 kW.
  • the power consumption decreased with time to come to be 8.5 kW after 10 minutes, and thereafter became constant at that value.
  • the subsequent procedure was repeated in the same manner as in Example 7 to obtain magenta toner particles.
  • the magenta toner particles thus obtained had a weight-average particle diameter of 6.7 ⁇ m.
  • the coefficient of variation in number distribution was 32%.
  • Example 7 The procedure of Example 7 was repeated except that the number of revolutions of the rotor was changed to 20.8 r.p.s. (peripheral speed: 14.4 m/s).
  • the motor for rotating the rotor at the drive initial stage showed a power consumption of 14.5 kW.
  • the power consumption decreased with time to come to be 9.5 kW after 10 minutes, and thereafter became constant at that value.
  • the magenta toner particles obtained had a weight-average particle diameter of 6.5 ⁇ m.
  • the coefficient of variation in number distribution was 29%.
  • the magenta toner particles obtained had a weight-average particle diameter of 6.6 ⁇ m.
  • the coefficient of variation in number distribution was 26%.
  • the dispersion was carried out at a number of revolutions of 8.3 r.p.s. (peripheral speed: 11.8 m/s) to obtain liquid monomer mixture.
  • the motor for rotating the rotor at the drive initial stage showed a power consumption of 38.5 kW.
  • the power consumption decreased with time to come to be 32 kW after 10 minutes, and thereafter became constant at that value.
  • the circulating pump was so controlled that the flow rate of the mixture was 3.6 m 3 /h and the circulation times was 32 times/h. Mill internal pressure was 245.2 kPa.
  • the same n-butyl acrylate monomer, saturated polyester resin and ester wax [Ester Compound (1)] as those used in Example 7 were dissolved in the same way, followed by addition of 10 parts by weight of a polymerization initiator 2,2'-azobis-(2,4-dimethylvaleronitrile).
  • the mixture obtained was put into the aqueous dispersion medium to carry out granulation for 13 minutes.
  • the high-speed stirrer was changed to a stirrer having propeller stirring blades and reaction was carried out for at 60°C for 5 hours, and then the liquid temperature was raised to 80°C to carry out the reaction for 10 hours.
  • magenta toner particles After the polymerization was completed, a portion of the slurry formed was sampled, and further washed and dried to measure physical properties of the magenta toner particles obtained.
  • the magenta toner particles thus obtained had a weight-average particle diameter of 6.5 ⁇ m as measured with the Coulter counter. The coefficient of variation in number distribution was 28%.
  • the magenta particles were found to have the structure as shown in Fig. 9 that the low-softening substance Ester Compound (1) was covered with the shell resin.
  • magenta toner particles thus obtained, 0.7 part by weight of hydrophobic fine silica powder having a specific surface area of 200 m 2 /g as measured by the BET method was externally added to obtain a magenta toner.
  • 93 parts by weight of an acryl-coated magnetic ferrite carrier was blended to produce a two-component developer.
  • the magenta toner particles obtained had a weight-average particle diameter of 8.0 ⁇ m.
  • the coefficient of variation in number distribution was 37%.
  • Magenta toner particles were obtained in the same manner as in Example 7 except that the number of revolutions of the rotor was changed to 5 r.p.s. (peripheral speed: 3.5 m/s).
  • the magenta toner particles obtained had a weight-average particle diameter of 9.8 ⁇ m.
  • the coefficient of variation in number distribution was 39%.
  • the magenta toner particles obtained had a weight-average particle diameter of 8.0 ⁇ m.
  • the coefficient of variation in number distribution was 36%.
  • Example 7 The procedure of Example 7 was repeated to obtain the aqueous dispersion medium.
  • a polymerizable monomer mixture having the same formulation as that of Example 7 was used.
  • the media type dispersion machine shown in Fig. 10 was loaded with media particles (material: zirconia) of 1 mm diameter at a packing of 1.23 x 10 -2 m 3 .
  • the monomer mixture was fed at a rate of 1 m 3 /h by means of a pump.
  • Dispersion was carried out by the circulation system at a rotor peripheral speed of 13 m/s for 60 minutes, thus a dispersion was prepared.
  • the procedure of Example 7 subsequent to the dispersion step was repeated to obtain magenta toner particles.
  • the magenta toner particles obtained had a weight-average particle diameter of 12.1 ⁇ m.
  • the coefficient of variation in number distribution was 48%.
  • Example 7 The procedure of Example 7 was repeated to obtain the aqueous dispersion medium.
  • a polymerizable monomer mixture having the same formulation as that of Example 7 was used.
  • the media type dispersion machine shown in Fig. 11 was loaded with media particles (material: zirconia) of 0.8 mm diameter at a packing of 7.5 x 10 -4 m 3 .
  • the monomer mixture was fed at a rate of 2.25 x 10 -3 m 3 /h by means of a pump.
  • Dispersion was carried out by the circulation system at a rotor peripheral speed of 13 m/s for 60 minutes, thus a dispersion was prepared.
  • the procedure of Example 7 subsequent to the dispersion step was repeated to obtain magenta toner particles.
  • the magenta toner particles obtained had a weight-average particle diameter of 11.3 ⁇ m.
  • the coefficient of variation in number distribution was 43%.
  • Example 7 The procedure of Example 7 was repeated to obtain the aqueous dispersion medium.
  • a polymerizable monomer mixture having the same formulation as that of Example 7 was heated to 60°C, and was fed into a medialess type dispersion machine Ebara Milder (manufactured by Eabara Seisakusho K.K.) at a feed rate of 180 kg/h by means of a pump. Dispersion was carried out by the circulation system at a number of rotor revolutions of 5,000 r.p.m. (peripheral speed: 15 m/s) for 60 minutes, thus a dispersion was prepared. The procedure of Example 7 subsequent to the dispersion step was repeated to obtain magenta toner particles. The magenta toner particles obtained had a weight-average particle diameter of 16.3 ⁇ m. The coefficient of variation in number distribution was 52%.
  • a process for producing a toner has the steps of dispersing a fine-particle colorant in a liquid monomer mixture containing at least a liquid polymerizable monomer, dispersing the resulting colorant-dispersed liquid monomer mixture in an aqueous dispersion medium to form particles of a polymerizable monomer composition, and polymerizing polymerizable monomers present in the particles in the aqueous dispersion medium to form toner particles.
  • a media particle agitation type wet-dispersion machine is used as a dispersion means.
  • the dispersion machine has a cylindrical vessel having a first wall surface having a liquid-feed opening and a second wall surface having a liquid-discharge opening.
  • the vessel is inside provided with an inner chamber and an outer chamber which are partitioned with a cylindrical separator having slits, a rotor set in the inner chamber rotatably by the rotary drive motion of a drive shaft, and a plurality of spherical media particles held in the inner chamber.

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  • Physics & Mathematics (AREA)
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JP3935315B2 (ja) * 1999-11-01 2007-06-20 キヤノン株式会社 重合法トナーの製造方法
JP3950743B2 (ja) * 2002-06-03 2007-08-01 キヤノン株式会社 トナー粒子の製造方法
US6951704B2 (en) * 2002-11-08 2005-10-04 Canon Kabushiki Kaisha Process for producing toner particles
JP4085931B2 (ja) * 2003-08-29 2008-05-14 日本ゼオン株式会社 重合トナーの製造方法
JP4665900B2 (ja) * 2004-06-22 2011-04-06 日本ゼオン株式会社 重合トナーの製造方法
US7494758B2 (en) * 2005-01-24 2009-02-24 Canon Kabushiki Kaisha Process for producing toner particles
US7682768B2 (en) * 2005-01-28 2010-03-23 Zeon Corporation Production process of polymerized toner
US7611816B2 (en) * 2005-07-29 2009-11-03 Canon Kabushiki Kaisha Process for producing toner particles
JP6452108B2 (ja) 2013-12-27 2019-01-16 キヤノン株式会社 トナー粒子の製造方法
DE102019101976B4 (de) 2018-01-30 2022-03-03 Canon Kabushiki Kaisha Toner und verfahren für die herstellung des toners
SE542677C2 (en) * 2018-05-18 2020-06-23 Valmet Oy Mixing apparatus comprising a rotor and a stator
JP7500260B2 (ja) 2020-04-10 2024-06-17 キヤノン株式会社 トナー
JP2022022127A (ja) 2020-07-22 2022-02-03 キヤノン株式会社 トナー
CN115318193B (zh) * 2022-08-11 2023-10-27 河南华索科技有限公司 一种铝电解槽用氟化铝与氧化铝混配装置及其实现方法

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EP0686885A1 (fr) * 1994-06-02 1995-12-13 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques
EP0730205A1 (fr) * 1995-02-28 1996-09-04 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques

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JPS5953856A (ja) 1982-09-21 1984-03-28 Canon Inc トナ−の製造方法
JPS5961842A (ja) 1982-09-30 1984-04-09 Canon Inc 磁性トナ−の製造方法
US5087546A (en) 1988-12-07 1992-02-11 Canon Kabushiki Kaisha Device for continuously mixing powder and process for producing toner for developing electrostatic image
JP3069933B2 (ja) 1992-06-26 2000-07-24 キヤノン株式会社 静電荷像現像用カラートナー
JP3010331B2 (ja) 1992-08-26 2000-02-21 キヤノン株式会社 静電荷像現像用重合トナーの製造方法
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EP0686885A1 (fr) * 1994-06-02 1995-12-13 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques
EP0730205A1 (fr) * 1995-02-28 1996-09-04 Canon Kabushiki Kaisha Révélateur pour le développement d'images électrostatiques

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